Field of the Invention
This invention relates to a method for the control of an industrial truck during order picking. The invention relates, in particular, to a method for the control of an industrial truck during order picking using an industrial truck that has at least one environment sensor to detect the relative position of an operator in the environment of the industrial truck.
Description of Related Art
On industrial trucks, in particular warehouse trucks that are designed to be used for order picking, the prior art includes generic walking pallet trucks, where the operator walks next to the vehicle, such as a pallet lift truck. The prior art also includes vehicles that have a driver's workplace to carry the driver. During the order picking itself, it is easy for the driver to leave this driver's workplace to pick up goods and, for example, place them on a pallet on a load fork.
For industrial trucks of this type, optical environmental sensors are known which detect the environment of the industrial truck. These sensors can be, for example, two-dimensional laser scanners (2-D laser scanners) or even three-dimensional laser scanners (3-D laser scanners), as well as optical sensors that measure distances, such as a time-of-flight camera. Using environmental sensors of this type, obstacles in the environment, roadways, positions of pallets as well as, in particular on order picker industrial trucks, the position of the industrial truck relative to a load shelf can be detected. For example, a laser scanner that measures the environment orthogonally to a mirror axis of rotation can be used for this purpose.
It is also known that to facilitate order picking, a warehouse truck or industrial truck can be moved by remote control, for example, by pushing a button on a remote control unit, in response to which the industrial truck continues to move as long as this signal continues to be transmitted. The industrial truck reacts automatically by means of the optical environmental sensors to changing distances from the load shelf, and automatically avoids obstacles as it travels. The industrial truck automatically maintains the proper distance from each side of the aisle between the load shelves.
One disadvantage of this method is that the industrial truck is positioned exactly as it is remotely controlled by the operator. For example, the forward travel of the industrial truck is interrupted at the instant the operator releases the forward button on a remote control unit. Therefore, it is left exclusively up to the operator to position the truck optimally or at the smallest possible distance between the position of an item to be picked and the point on the industrial truck where it is to be deposited. As a result of the requirement that the operator is the only one who can exercise this control, the operator must concentrate entirely on forward travel to the next order picking position. Therefore, the operator is holding the remote control unit in his hand and his hand is not free to pick up the next item. If, for example, an order picking truck with a long load fork is to be positioned for two pallets, the operator must drive individually to each of the positions to load a forward pallet or a rear pallet.